US President Barack Obama has arrived in Turkey on a two-day visit, after giving his support to Ankara's efforts to join the European Union.
He said Turkey's accession to the EU would send an important signal to the Muslim world and firmly anchor the country in Europe.
But French President Nicolas Sarkozy said it was up to the EU itself to decide who joined the bloc.
Correspondents say security is extremely tight for Mr Obama's visit.
Snipers and riot police have been deployed and military aircraft are patrolling a no-fly zone over Ankara, AP news agency reported.
Almost 9,000 police will be deployed for Mr Obama's visit to Turkey's largest city, Istanbul, which begins late on Monday.
Several small groups have been holding anti-US demonstrations in both cities, the AP said.
The visit is Mr Obama's first to a majority Muslim country as president, and only his second purely bilateral visit after Canada.
The BBC's Sarah Rainsford in Ankara says the fact that he chose to come to Turkey so early has been welcomed as a sign that he wants to re-engage with it.
Public support for the US dropped to a record low during the Bush administration, fuelled mostly by fierce opposition to the invasion of Iraq, she says.
Speaking in Prague earlier on Sunday, Mr Obama said Turkey's entry into the EU would help to consolidate its position as a Western nation.
"The United States and Europe must approach Muslims as our friends, neighbours and partners in fighting injustice, intolerance and violence, forging a relationship based on mutual respect and mutual interest," he said.
"Moving forward towards Turkish membership in the EU would be an important signal of your commitment to this agenda and ensure that we continue to anchor Turkey firmly in Europe."
But Mr Sarkozy said he had always been opposed to Turkey's EU entry.
"I have been working hand-in-hand with President Obama but when it comes to the European Union it's up to member states of the European Union to decide," he told French TV.
German Chancellor Angela Merkel said that while close links with Turkey were important, its future status in Europe was still open for discussion.
The EU agreed to open accession talks with Ankara in 2004, but in recent years, correspondents say, Turkey has made little progress with democratic reforms which would improve its chances of membership.
http://news.bbc.co.uk/2/hi/europe/7984762.stmQuelle surprise!